As one process for manufacturing a semiconductor device, a process of forming a nitride film, such as a silicon nitride film (Si3N4 film, hereinafter, also referred to as an SiN film) or the like as a protective film on a substrate on which an oxide film such as a silicon oxide film (SiO2 film, hereinafter, also referred to as an SiO film) or the like is formed, is often performed. When an etching process is performed on the substrate, the oxide film can be protected by the nitride film formed on the oxide film.
However, if a film thickness of the nitride film is thin, the function of the nitride film as the protective film may be lowered. As a result, when an etching process is performed on the substrate, the oxide film may be damaged. The present disclosure provides some embodiments of a technique capable of suppressing a degradation of a function of a nitride film as a protective film.